Configuring the Fabric Interconnects
This chapter includes the following sections:
- Initial System Setup
- Performing an Initial System Setup for a Standalone Configuration
- Enabling a Standalone Fabric Interconnect for Cluster Configuration
- Ethernet Switching Mode
- Configuring Ethernet Switching Mode
- Setup Mode
- System Configuration Type
- Management Port IP Address
- Performing an Initial System Setup for the First Fabric Interconnect
- Performing an Initial System Setup for the Second Fabric Interconnect
Initial System Setup
The first time that you access a fabric interconnect in a Cisco UCS instance, a setup wizard prompts you for the following information required to configure the system:
Setup Mode
You can choose to either restore the system configuration from an existing backup file, or manually setup the system by going through the setup wizard. If you choose to restore the system, the backup file must be reachable from the management network.
System Configuration Type
You can configure a Cisco UCS instance to use a single fabric interconnect in a standalone configuration or to use a redundant pair of fabric interconnects in a cluster configuration.
A cluster configuration provides high availability. If one fabric interconnect becomes unavailable, the other takes over. Only one management port (Mgmt0) connection is required to support a cluster configuration; however, both Mgmt0 ports should be connected to provide link-level redundancy.
Note |
The cluster configuration only provides redundancy for the management plane. Data redundancy is dependent on the user configuration and may require a third-party tool to support data redundancy. |
To use the cluster configuration, the two fabric interconnects must be directly connected together using Ethernet cables between the L1 (L1-to-L1) and L2 (L2-to-L2) high availability ports, with no other fabric interconnects in between. This allows the two fabric interconnects to continuously monitor the status of each other and quickly know when one has failed.
Both fabric interconnects in a cluster configuration must go through the initial setup process. The first fabric interconnect to be setup must be enabled for a cluster configuration, then when the second fabric interconnect is setup, it detects the first fabric interconnect as a peer fabric interconnect in the cluster.
For more information, refer to the Cisco UCS 6100 Series Fabric Interconnect Hardware Installation Guide.
Management Port IP Address
In a standalone configuration, you must specify only one IP address and the subnet mask for the single management port on the fabric interconnect.
In a cluster configuration, you must specify the following three IP addresses in the same subnet:
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Management port IP address for fabric interconnect A
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Management port IP address for fabric interconnect B
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Cluster IP address
Tip |
After the initial configuration, you can change the management IP port and the related subnet mask in the Cisco UCS Manager CLI. You cannot make this change in the Cisco UCS Manager GUI. |
Performing an Initial System Setup for a Standalone Configuration
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Verify the following physical connections on the fabric interconnect:
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The console port is physically connected to a computer terminal or console server.
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The management Ethernet port (mgmt0) is connected to an external hub, switch, or router.
For more information, refer to the Cisco UCS Hardware Installation Guide for your fabric interconnect.
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Verify that the console port parameters on the computer terminal (or console server) attached to the console port are as follows:
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Collect the following information that you will need to supply during the initial setup:
The following example sets up a standalone configuration using the console:
Enter the installation method (console/gui)? console Enter the setup mode (restore from backup or initial setup) [restore/setup]? setup You have chosen to setup a new switch. Continue? (y/n): y Enter the password for "admin": adminpassword%958 Confirm the password for "admin": adminpassword%958 Do you want to create a new cluster on this switch (select 'no' for standalone setup or if you want this switch to be added to an existing cluster)? (yes/no) [n]: no Enter the system name: foo Mgmt0 IPv4 address: 192.168.10.10 Mgmt0 IPv4 netmask: 255.255.255.0 IPv4 address of the default gateway: 192.168.10.1 Configure the DNS Server IPv4 address? (yes/no) [n]: yes DNS IPv4 address: 20.10.20.10 Configure the default domain name? (yes/no) [n]: yes Default domain name: domainname.com Following configurations will be applied: Switch Fabric=A System Name=foo Management IP Address=192.168.10.10 Management IP Netmask=255.255.255.0 Default Gateway=192.168.10.1 DNS Server=20.10.20.10 Domain Name=domainname.com Apply and save the configuration (select 'no' if you want to re-enter)? (yes/no): yes
Initial System Setup for a Cluster Configuration
Performing an Initial System Setup for the First Fabric Interconnect
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Verify the following physical connections on the fabric interconnect:
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A console port on the first fabric interconnect is physically connected to a computer terminal or console server.
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The management Ethernet port (mgmt0) is connected to an external hub, switch, or router.
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The L1 ports on both fabric interconnects are directly connected to each other.
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The L2 ports on both fabric interconnects are directly connected to each other.
For more information, refer to the Cisco UCS Hardware Installation Guide for your fabric interconnect.
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Verify that the console port parameters on the computer terminal (or console server) attached to the console port are as follows:
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Collect the following information that you will need to supply during the initial setup:
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System name
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Password for the admin account
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Three static IP addresses: two for the management port on both fabric interconnects (one per fabric interconnect), and one for the cluster IP address used by Cisco UCS Manager
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Subnet mask for the three static IP addresses
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Default gateway IP address
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DNS server IP address (optional)
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Domain name for the system (optional)
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The following example sets up the first fabric interconnect for a cluster configuration using the console:
Enter the installation method (console/gui)? console Enter the setup mode (restore from backup or initial setup) [restore/setup]? setup You have chosen to setup a new switch. Continue? (y/n): y Enter the password for "admin": adminpassword%958 Confirm the password for "admin": adminpassword%958 Do you want to create a new cluster on this switch (select 'no' for standalone setup or if you want this switch to be added to an existing cluster)? (yes/no) [n]: yes Enter the switch fabric (A/B): A Enter the system name: foo Mgmt0 IPv4 address: 192.168.10.10 Mgmt0 IPv4 netmask: 255.255.255.0 IPv4 address of the default gateway: 192.168.10.1 Virtual IPv4 address : 192.168.10.12 Configure the DNS Server IPv4 address? (yes/no) [n]: yes DNS IPv4 address: 20.10.20.10 Configure the default domain name? (yes/no) [n]: yes Default domain name: domainname.com Following configurations will be applied: Switch Fabric=A System Name=foo Management IP Address=192.168.10.10 Management IP Netmask=255.255.255.0 Default Gateway=192.168.10.1 Cluster Enabled=yes Virtual Ip Address=192.168.10.12 DNS Server=20.10.20.10 Domain Name=domainname.com Apply and save the configuration (select 'no' if you want to re-enter)? (yes/no): yes
Performing an Initial System Setup for the Second Fabric Interconnect
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Verify the following physical connections on the fabric interconnect:
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A console port on the second fabric interconnect is physically connected to a computer terminal or console server.
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The management Ethernet port (mgmt0) is connected to an external hub, switch, or router.
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The L1 ports on both fabric interconnects are directly connected to each other.
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The L2 ports on both fabric interconnects are directly connected to each other.
For more information, refer to the Cisco UCS Hardware Installation Guide for your fabric interconnect.
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Verify that the console port parameters on the computer terminal (or console server) attached to the console port are as follows:
-
Collect the following information that you will need to supply during the initial setup:
The following example sets up the second fabric interconnect for a cluster configuration using the console:
Enter the installation method (console/gui)? console Installer has detected the presence of a peer switch. This switch will be added to the cluster. Continue?[y/n] y Enter the admin password of the peer switch: adminpassword%958 Mgmt0 IPv4 address: 192.168.10.11 Management Ip Address=192.168.10.11 Apply and save the configuration (select 'no' if you want to re-enter)? (yes/no): yes
Enabling a Standalone Fabric Interconnect for Cluster Configuration
You can add a second fabric interconnect to an existing Cisco UCS instance that uses a single standalone fabric interconnect. To do this, you must enable the standalone fabric interconnect for cluster operation, and then add the second fabric interconnect to the cluster.
Command or Action | Purpose | |
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Step 1 | UCS-A# connect local-mgmt | Enters local management mode. |
Step 2 | UCS-A(local-mgmt) # enable cluster ip-addr | Enables cluster operation on the standalone fabric interconnect with the specified IP address. When you enter this command, you are prompted to confirm that you want to enable cluster operation. Type yes to confirm. |
The following example enables a standalone fabric interconnect with IP address 192.168.1.101 for cluster operation:
UCS-A# connect local-mgmt
UCS-A(local-mgmt)# enable cluster 192.168.1.101
This command will enable cluster mode on this setup. You cannot change it
back to stand-alone. Are you sure you want to continue? (yes/no): yes
UCS-A(local-mgmt)#
Add the second fabric interconnect to the cluster.
Ethernet Switching Mode
The Ethernet switching mode determines how the fabric interconnect behaves as a switching device between the servers and the network. The fabric interconnect operates in either of the following Ethernet switching modes:
End-Host Mode
End-host mode allows the fabric interconnect to act as an end host to the network, representing all server (hosts) connected to it through vNICs. This is achieved by pinning (either dynamically pinned or hard pinned) vNICs to uplink ports, which provides redundancy toward the network, and makes the uplink ports appear as server ports to the rest of the fabric. When in end-host mode, the fabric interconnect does not run the Spanning Tree Protocol (STP) and avoids loops by denying uplink ports from forwarding traffic to each other, and by denying egress server traffic on more than one uplink port at a time. End-host mode is the default Ethernet switching mode and should be used if either of the following are used upstream:
Note |
When end-host mode is enabled, if a vNIC is hard pinned to an uplink port and this uplink port goes down, the system cannot re-pin the vNIC, and the vNIC remains down. |
Switch Mode
Switch mode is the traditional Ethernet switching mode. The fabric interconnect runs STP to avoid loops, and broadcast and multicast packets are handled in the traditional way. Switch mode is not the default Ethernet switching mode, and should be used only if the fabric interconnect is directly connected to a router, or if either of the following are used upstream:
Note |
For both Ethernet switching modes, even when vNICs are hard pinned to uplink ports, all server-to-server unicast traffic in the server array is sent only through the fabric interconnect and is never sent through uplink ports. Server-to-server multicast and broadcast traffic is sent through all uplink ports in the same VLAN. |
Configuring Ethernet Switching Mode
When you change the Ethernet switching mode, Cisco UCS Manager logs you out and restarts the fabric interconnect. For a cluster configuration, Cisco UCS Manager restarts both fabric interconnects sequentially. The second fabric interconnect can take several minutes to complete the change in Ethernet switching mode and become system ready.
Command or Action | Purpose | |
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Step 1 | UCS-A# scope eth-uplink | Enters Ethernet uplink mode. |
Step 2 | UCS-A /eth-uplink # set mode {end-host | switch} | Sets the fabric interconnect to the specified switching mode. |
The following example sets the fabric interconnect to end-host mode:
UCS-A# scope eth-uplink UCS-A /eth-uplink # set mode end-host